My air rifle seems to be changing vertical accuracy overnight without explanation. I have a Crosman 1377 with a long barrel and I have been shooting with it often, mostly elevated shots (at targets higher than the shooter). The lateral accuracy is consistent, but vertical accuracy changes every week overnight. One day it shoots straight aligned with the sight, the next day it shoots lower, well below the sight. A week or two later it shoots higher than the sight. This change happens overnight and I am baffled and bamboozled. So I find myself missing the target and have to recalibrate. One day It shot so low that I dismantled the rifle, cleaned the barrel and readjusted the air seals and air ring, reassembled it and it shot higher. But I could not determine what caused the change in vertical accuracy. I still can't find an explanation as to why or what causes the air-gun to change vertical accuracy overnight.
What's worng with my air gun ?
- Thread starter sprotz
- Start date
Scope or open sights?
If scoped, it’s probably due to the slop in the barrel band where it secures to the end of the pump tube which will cause the barrel to shift.
If open sights, I don’t know unless there is a velocity issue. Do you have access to a chronograph?
If scoped, it’s probably due to the slop in the barrel band where it secures to the end of the pump tube which will cause the barrel to shift.
If open sights, I don’t know unless there is a velocity issue. Do you have access to a chronograph?
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Are you using the stock rear sight? Something to check is that the notch part of the sight is secure. On my 1322 the screw on the vertical part of the sight would back out, eventually all the re-tightening stripped the plastic and I put in a larger screw. Might be worth a look.
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If your 1377 still has the factory breech, might be inadequate support and anchoring for the long barrel. A good, STURDY aftermarket breech might solve your problem.
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Hi!!
It is silly but I suppose that when you shoot it does not support the barrel in any support
Regards
Enkey
It is silly but I suppose that when you shoot it does not support the barrel in any support
Regards
Enkey
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Sounds like a loose barrel or a loose breech and barrel to me. Make sure everything's tightened up and try again. YO!
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It might be the barrel and breech shifting, but the breech looks secure enough. To answer one of your questions,, the breech is the plastic factory breech, and I press on the breech / barrel when pumping, so it is possible that both might be shifting slightly, and also disorganizing the air seals.
I will get a steel breech next time when I can.
The rear sight looks secure, but it was a problem in the past.
I will get a steel breech next time when I can.
The rear sight looks secure, but it was a problem in the past.
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The front of the barrel rests on the frame of the window, and the buttstock is against my cheek or shoulder, while I hold the pistol grip.
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No, No, No! Support the forearm of the stock and never touch the barrel when shooting. Most guys simply let the forestock lay loosely on their hand.
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